The fuel economy of a 2006 Ford Mustang varies significantly depending on the engine and transmission. There wasn't a single engine option that year. To get an accurate MPG estimate, you need to know the specific engine (e.g., 4.0L V6, 4.6L V8) and whether it has an automatic or manual transmission.
You'll find the most accurate MPG figures in the owner's manual for that specific vehicle or on the EPA's fueleconomy.gov website by searching for the year, make, model, and engine.
